PHP Undefined Index [duplicate]

Answer 1

I don't see php file, but that could be that -
replace in your php file:

$query_age = $_GET['query_age'];

with:

$query_age = (isset($_GET['query_age']) ? $_GET['query_age'] : null);

Most probably, at first time you running your script without ?query_age=[something] and $_GET has no key like query_age.

Answer 2

The first time you run the page, the query_age index doesn't exist because it hasn't been sent over from the form.

When you submit the form it will then exist, and it won't complain about it.

#so change
$_GET['query_age'];
#to:
(!empty($_GET['query_age']) ? $_GET['query_age'] : null);

Answer 3

if you use isset like the answer posted already by singles, just make sure there is a bracket at the end like so:
$query_age = (isset($_GET['query_age']) ? $_GET['query_age'] : null);

Answer 4

The checking of the presence of the member before assigning it is, in my opinion, quite ugly.

Kohana has a useful function to make selecting parameters simple.

You can make your own like so...

function arrayGet($array, $key, $default = NULL)
{
    return isset($array[$key]) ? $array[$key] : $default;
}

And then do something like...

$page = arrayGet($_GET, 'p', 1);